Machining operations often comprise the production of a number of identical parts, each of which involves cutting, drilling, milling or other machining operations at precise locations on the part or work piece. A major part of the time consumed in such operations involves the initial set-up, i.e. the positioning of the vise and the positioning of the part in the vise jaws relative to the cutting blade, drill bit or other machine tool being used. For repetition of the same operation on successive parts, the position of the vise can not be disturbed between machining of the various parts, but unless some means is provided for quickly and precisely positioning each successive part at the same location in the vise jaws, the time spent on this machining process can be considerable. The present invention concerns an attachment for a vise in the form of an adjustable vise stop which serves as a convenient and precise means for positioning successive work pieces at the same location in the vise jaws.